A NATIONAL chain of book-makers has vowed to step up security at its Rugby branches after armed robbers raided a fourth outlet in 10 weeks.

The latest attack happened when a man forced open the door of Coral in Railway Terrace, and threatened staff with a kitchen knife.

Workers were cashing up at about 9.30pm on Monday when the robber burst through the doors, brandishing a knife with a four-inch blade.

He ordered terrified staff to put the day's takings into a black carrier bag, which had the words "I paid" written in yellow and white on the side.

It has not been revealed how much cash was stolen.

The robber was described as white, in his mid-20s, 5ft 10in to 6ft, of medium build, with blond streaked hair. He wore a baseball cap which was white with a triangular pattern on it, a black jacket and dark jogging bottoms, both with white stripes, a cream or white scarf tied round his face, and black gloves.

Although he kicked out at a woman outside the premises, no one was hurt in the attack. He fled on foot.

The raid follows armed robberies at three other Coral shops in the town.

The branch at The Green, in Bilton, was hit on New Year's Eve - just days after a police campaign was launched to protect bookies and other premises vulnerable to cash robbery.

In that incident two men entered the shop, one brandishing what was believed to have been a shotgun, and the other a knife.

Staff behind the till were threatened and a 22-year-old member of staff was assaulted.

The raiders, who wore balaclavas, escaped with cash in a red Ford Mondeo car, later found abandoned in The Heath, Dunchurch.

Police had arrested four people in connection with the Bilton branch raid. Two men, aged 25 and 30, were seized at an address in Hillmorton, while a 17-year-old youth and a 22-year-old man, were released on police bail following their arrests on New Year's Day.

A fortnight earlier, robbers had struck twice in two days. A gunman held up the Bridget Street branch on Friday, December 14, while a lone raider wielded two knives at the Kingsway store.

At the time, police said they were not linking any of the raids.

A spokesman for Coral said yesterday: "We're constantly reviewing security measures. But now we'll pay even closer attention.

"We don't want to discuss publicly the measures we'll take, because we don't want to make our staff and customers any more vulnerable.

"It's deeply upsetting for everyone, but fortunately no one has been seriously injured in any of the incidents.

"We're certainly not a soft target. The incidents don't seem to be linked, they're just indicative of society today. It's not a problem exclusive to Coral. I don't know why people have been targeting us in this way, there's never as much money in bookmakers as people imagine."